( Adopted : 11/04/77; Amended: 09/01/78; Amended : 02/02/79; Amended 01/08/82; Amended : 05/06/83; Amended 05/04/90; Amended: 04/05/91; Amended : 09/11/92; Amended : 10/02/92; Amended : 11/17/95; Amended : 08/21/12)

AVAQMD Rule 431.1 431.1-1 Sulfur Content of Gaseous Fuels 

## RULE 431.1

Sulfur Content of Gaseous Fuels

(A) General

(1) Purpose
(a) The purpose of this rule is to reduce sulfur ox ides (SO x ) emissions from the burning of gaseous fuels in stationary equipmen t.
(2) Applicability
(a) The provisions of this rule shall apply to any burning, transferring, selling or the offering for sale of any gaseous fuels conta ining sulfur compounds in excess of 16 parts per million by volume (ppmv), calculated as hydrogen sulfide (H 2 S), in stationary equipment requiring a Permit to Operate (PTO) by the Antelope Valley Air Quality Ma nagement District (District).



### (B) Definitions

(1) “Air Pollution Control Officer” (APCO) – The pe rson appointed to the position of Air Pollution Control Officer of the District pursu ant to the provisions of California Health & Safety Code §40750, and his or her designee.
(2) “Authority to Construct Permit” (ATC) – A Distr ict permit required pursuant to the provisions of District Rule 201 which must be o btained prior to the building, erecting, installation, alteration or replacement o f any Permit Unit. Such permit may act as a temporary PTO pursuant to the provisio ns of District Rule 202.
(3) Burn – To combust any gaseous fuel, whether for useful heat or by incineration without heat recovery, except for flaring of emerge ncy vent gases.
(4) “California Air Resources Board” (CARB) – The C alifornia State Air Resources Board the powers and duties of which are described in Part 2 of Division 26 of the California Health & Safety Code (commencing with se ction 39500).
(5) Continuous Emission Monitoring System (CEMS) – A system of equipment that continuously measures and records all parameters ne cessary to directly determineAVAQMD Rule 431.1 Sulfur Content of Gaseous Fuels 431.1-2 concentrations and/or mass emissions of selected po llutants, and which meets all

of the requirements of Attachment A, Section II.
(6) Continuous Fuel Gas Monitoring System” (CFGMS) – A system of equipment that continuously measures and records total sulfur concentration in the gaseous fuel prior to burning, and which meets all the requ irements of Attachment A, Section I.

(7) “Continuous Monitor” – a CEMS or CFGMS.
(8) Daily Average – An arithmetic mean of all of a facility’s sulfur compounds readings within a calendar day obtained according t o the guideline specified in Attachment A.
(9) “District” – The Antelope Valley Air Quality Ma nagement District, the geographical area of which is described in District Rule 103.
(10) Emergency Vent Gas – Any gas released from a p rocess unit as a result of any process upset or breakdown.
(11) Gaseous Fuel – Any gaseous material which rele ases heat when burned including, but not limited to, any natural, refinery, field pr oduced, process, synthetic, landfill, sewage digester, or waste gases with a gross heatin g value of 2670 kilocalories per cubic meter (300 BTU per cubic foot) or higher, at standard conditions.
(12) Landfill Gas – Any gas derived through any bio logical process from the decomposition of organic waste buried within a wast e disposal site.
(13) Monthly Weighted Average Sulfur Content – The result of the summation of average daily sulfur contents of the fuel(s) consum ed multiplied by the average daily consumption rates of the fuel(s) consumed in any month divided by the total gaseous fuel consumption rate for that month.
(14) Natural Gas – A mixture of gaseous hydrocarbon s, with at least 80 percent methane (by volume), and of pipeline quality, such as the gas sold or distributed by any utility company regulated by the California Public Utilities Commission.
(15) “Permit to Operate” (PTO) – A District permit required pursuant to the provisions of District Rule 203 which must be obtained prior t o operation of a Permit Unit. An ATC may function as a temporary PTO pursuant to the provisions of District Rule 202.
(16) Refinery Gas – Any combustible gaseous by-prod uct generated from a petroleum refinery process unit operation, with a gross heati ng value of 2670 kilocalories per cubic meter (300 BTU per cubic foot) or higher, at standard conditions.AVAQMD Rule 431.1

Sulfur Content of Gaseous Fuels 431.1-3 (17) Sewage Digester Gas – Any gas derived from ana erobic decomposition of organic sewage within its containment.
(18) “South Coast Air Quality Management District” – The air quality district created pursuant to Division 26, Part 3, Chapter 5.5 of the California Health & Safety Code (commencing with §40400).
(19) Standard Conditions – The atmospheric state wh ere the temperature is 60°F and barometric pressure is 14.7 pounds per square inch absolute.
(20) Stream Day – Any day or part of a day when a f acility or a process unit is in operation.
(21) “United States Environmental Protection Agency ” (USEPA) - The United States Environmental Protection Agency, the Administrator of the USEPA and his or her authorized representative.



### (C) Requirements

(1) Natural gas
A person shall not sell or offer for sale for use i n the jurisdiction of the District natural gas containing sulfur compounds, calculated as H 2 S, in excess of 16 parts per million by volume (ppmv).

(2) Other Gaseous Fuels
A person shall not burn in equipment requiring a PT O, purchase, transfer, sell or offer for sale for use in the jurisdiction of the D istrict, any gaseous fuel containing sulfur compounds, calculated asH 2 S, in excess of the concentration limits as measured over the averaging periods for various gas eous fuels as specified in Table 1.

TABLE 1
Fuel Type Sulfur Limits ppmv Averaging Periods

Refinery Gas 40 4 hrs

Landfill Gas 250 Daily

Sewage Digester Gas 40 or Daily or

40 and 500 Monthly and 15-minutes

Other Gases 40 4 hrsAVAQMD Rule 431.1 Sulfur Content of Gaseous Fuels 431.1-4 (3) Previously Exempt or Previously Compliant Facil ities
A person burning gaseous fuel containing sulfur com pounds in excess of the limits specified in Table 1 and whose facility had been previously exempt from this rule pursuant to subsection (G)(6); or any per son who, without the use of any sulfur removal or control system, had been previous ly in compliance with the limits specified in Table 1, shall:
(a) Submit for approval by the APCO within 30 days from the time of exceedance or non-compliance, a plan to demonstrate compliance with the requirements of the rule;
(b) Submit to the APCO an application for a fuel ga s control system within six months of the time of exceedance of the exemption c riteria specified in subsection (G)(6), or non-compliance with the limit ;
(c) Demonstrate compliance with the limit specified in Table 1 no later than 18 months after the time of exceedance; and
(d) Comply with subsections (D)(1) and (D)(2), or ( D)(3).



### (D) Monitoring Requirements

(1) Except as provided in subsection (D)(3), a pers on burning gaseous fuels, other than exclusively natural gas, in stationary equipme nt requiring a PTO by the District shall have a properly operating continuous fuel gas monitoring system (CFGMS) to determine the sulfur content, calculated as H 2 S, of the fuel gas prior to burning, or a continuous emission monitoring sys tem (CEMS) to determine SO x emissions after burning. All continuous monitors, require District approval, which shall be based on the requirements as specifi ed in Attachment A.

( a ) A person shall install the CFGMS upstream of any mixing of refinery gases with natural gas, propane or other fuels.
(b) A person subject to subsection (C)(3) of this r ule shall comply with subsections (D)(1) and (D)(2) no later than twelve months after the date an ATC is issued by the District for a sulfur removal system or comply with subsection (D)(3).
(c) Compliance with the Table 1 sulfur limits shall be determined based on readings obtained from an approved Continuous Monit or.
(2) A person installing a Continuous Monitor shall submit to the District for approval, a quality assurance procedure as specified in USEPA 40 CFR Part 60, Appendix F, Procedure 1 for CEMS and, as applicable, for CFG MS.AVAQMD Rule 431.1

Sulfur Content of Gaseous Fuels 431.1-5

(a) The quality assurance procedure specified above shall be submitted to the District for written approval by the APCO prior to the CFGMS or CEMS final certification.
(b) Any CFGMS or CEMS deemed to be out of control, as specified in Attachment A, according to the facility quality ass urance procedure approved by the APCO shall be corrected within 72 h ours.
(i) The person operating the CFGMS or CEMS shall no tify the APCO by telephone or facsimile of any breakdown(s) of th e monitoring systems if the duration of the breakdown is in exce ss of 60 minutes or if there are three (3) or more breakdowns in any one day within 24 hours of the occurrence of the breakdown which t riggers notification. Such report shall identify the time, location, equipment involved, and contact person. (ii) The person who complies with the provisions of subs ection (D)(2)(b)(i) and subsection (E) (3) shall not be co nsidered in violation of this rule for the 72 hour period of br eakdown provided that the breakdown did not result from operator err or, neglect or improper operation or maintenance procedures.

(3) A person burning landfill gas or sewage digeste r gas, or who is subject to subsection (C)(3) of this rule may use an alternati ve monitoring method, in lieu of the requirements in subsections (D)(1) and (D)(2), that ensures compliance with the daily total sulfur content limitation as specif ied in Table 1. Alternative monitoring methods shall not be used unless first a pproved in writing by the APCO, the California Air Resources Board (CARB), an d the Regional Administrator of the Environmental Protection Agenc y (EPA), Region IX, or their designees.
(a) At a minimum, the alternative monitoring method shall meet the guidelines of Attachment A, Section III.
(b) A person subject to subsection (C)(3) of this r ule shall submit an alternative monitoring method for approval no later than 45 days after the date an ATC for a sulfur removal system is issued.
(c) All monitoring must comply with the approved al ternative monitoring method.
(d) District personnel shall use the approved alter native monitoring method to determine compliance with the limits of this rule.AVAQMD Rule 431.1 Sulfur Content of Gaseous Fuels 431.1-6 

### (E) Reporting and Recordkeeping Requirements

(1) All records required by this rule shall be main tained at the facility for at least five (5) years, and be made available to District staff upon request.
(2) Except at electric utility generating facilitie s and refineries, a person burning gaseous fuel, other than exclusively natural gas, i n stationary equipment requiring a PTO, shall submit to the APCO annual reports of t he monthly fuel consumption and the total sulfur content of the fuel consumed. The annual report shall be submitted no later than 60 days following the end o f the reporting year, and shall consist of the amount of any gaseous fuel consumed monthly, the applicable hourly, daily or monthly average sulfur content as determined by the Continuous Monitor or approved alternative monitoring method a s specified in subsections (D)(1), (D)(2), or (D)(3) of this rule, and total S O x emissions, calculated as SO 2 . (3) A person burning gaseous fuel in stationary equ ipment located at electric utility generating facilities or refineries shall submit to the APCO monthly reports of the daily fuel consumption, the monthly weighted averag e sulfur content (except for natural gas), and the maximum four (4)-hour average sulfur content of the fuel consumed, as determined by the device specified in subsection (D)(2) of this rule and the total SO x emissions, calculated as SO 2 . The report shall be submitted no later than 30 days following the end of the reporti ng month.
(4) The person operating a continuous monitor shall keep records as specified in clause (D)(2)(b)(i) for monitor breakdown (s)



### (F) Test Methods

The following may be used by the APCO to verify com pliance with the provisions of this rule:

(1) For determination of compliance with sulfur con tent requirements of section (C):
(a) The reference method for determining the concen tration of sulfur compounds in a gaseous fuel, calculated as H 2 S, shall be South Coast Air Quality Management District (SCAQMD) Method 307-91 - Determination of Sulfur in a Gaseous Matrix, or any other method demonstrated by the applicant to be equivalent and approved in writing by the APCO, the CARB, and the Regional Administrator of the EPA, Re gion IX, or their designees, orAVAQMD Rule 431.1

Sulfur Content of Gaseous Fuels 431.1-7

(b) Data obtained from a continuous monitor, which is required to be installed and properly operated according to section (D) and as approved by the APCO pursuant to the requirements specified in Atta chment A.
(2) The gross heating value of gaseous fuels shall be determined by ASTM Method D 3588-91 or, if applicable, ASTM Method D 4891-89.
(3) The methane content of gaseous fuels shall be d etermined by ASTM Method D 1945-81.



### (G) Exemptions

Unless otherwise specified, and provided that the p erson seeking the exemption supplies proof and verification upon request of applicable c riteria to the satisfaction of the APCO, the provisions of this rule shall not apply to the following:
(1) A person selling, for use in the jurisdiction o f the District, any gaseous fuel not complying with subsections (C)(1) and (C)(3) provid ed that:
(a) The gaseous fuel is delivered directly to a sul fur removal unit which is in full operation and which reduces the sulfur content to the limits specified in subsections (C)(1) and (C)(3);
(b) The seller notifies the APCO prior to any such sale of the quantity, heating value, and composition of the gaseous fuel to be so ld; and
(c) The buyer has an approved ATC and/or PTO for th e sulfur removal unit that will be used to treat the purchased gas.
(2) Gaseous fuels containing sulfur used in the pro duction of sulfur or sulfur compounds.
(3) Waste gases being burned provided that:
(a) The gross heating value of such gases is less t han 2670 kilocalories per cubic meter (300 British Thermal Units per cubic fo ot) at standard conditions; and
(b) Any supplemental fuel used to burn such waste g ases does not contain sulfur or sulfur compounds in excess of the amount specified in this rule.
(4) Gases vented to a control system pursuant to Di strict Rule1173

. (5) Gases vented intermittently to fuel gas or wast e disposal system from pressure control valves, sight glasses, compressor bottles, sampling systems, and pump and compressor case vents.AVAQMD Rule 431.1 Sulfur Content of Gaseous Fuels 431.1-8 (6) Any facility which emits less than five (5) pou nds per day total sulfur compounds,

calculated as H 2 S, from the burning of gaseous fuels other than nat ural gas. Emissions of total sulfur compounds shall be measur ed based on fuel analysis, using the test method specified in subsection (F)(1 ), and the maximum daily gaseous fuel consumption. This exemption shall not apply to the requirement of subsection (C)(1).
(7) A person is exempt from the requirements of sub section (D)(1) if the person demonstrates to the satisfaction of the APCO that t he supplier of the gaseous fuel has complied with the requirements of section (D) f or such fuel.
(8) On or after July 1, 1997, a person previously i n compliance with the limits specified in Table 1 of this rule shall be exempt f rom the requirements of subsection (C)(3) provided that: the alternative m onitoring method pursuant to section (D) yields no more than three individual re adings in a calendar year in excess of the limits specified in Table 1; that no single reading exceeds a fuel sulfur limit by 25 percent; and that the sampling f requency is no longer than once per week.

See SIP Table at http://www.avaqmd.ca.gov/Modules/S howDocument.aspx?documentid=921AVAQMD Rule 431.1

Sulfur Content of Gaseous Fuels 431.1-9 

### ATTACHMENT A

SECTION I REQUIREMENTS FOR CONTINUOUS FUEL GAS MONITORING SYSTEM (CFGMS)

A continuous fuel gas monitor used for determining the sulfur content of any gaseous fuel shall:

(1) Continuously monitor and record the concentrati on by volume (dry basis) of sulfur compounds in ppmv as H 2 S in the gaseous fuel. (2) Have the span value of the monitor set so that all readings fall between 20 and 95 percent of scale. (3) Check for calibration drift of the monitoring s ystem at least once daily (approximately 24- hr interval) at two concentrations, one high level and one low level. Whenever the daily high level or low level calibration drift exceeds 5 % of analyzer full scale span, the monitoring system shall be deemed to be out of cont rol and subject to the requirements of subsection (D)(2(b) of this rule. (4) Determine the relative accuracy of the monitor which shall be no greater than 20 percent of the mean value of the reference method test data

. (5) Be able to record negative values of zero drift

. (6) Report the concentration of the sulfur compound s calculated as H 2 S.

SECTION II REQUIREMENTS FOR CONTINUOUS EMISSIONS MONITORING SYSTEMS (CEMS)

A stack CEMS used for monitoring the sulfur dioxide emissions from the burning of any gaseous fuel shall:

(1) Continuously monitor and record the concentrati on by volume (dry basis, zero percent excess air) of sulfur compounds in ppmv as SO 2 emitted into the atmosphere; (2) Include either an oxygen monitor for correcting the data for excess air or a fuel gas and exhaust gas flowmeter for the determination of mass emissions; (3) Have the span value of all the monitors set so that all readings fall between 20 and 95 percent, for four-hour and daily averages, and betw een 10 and 95 percent, for monthly averages, of full scale; (4) When using an oxygen monitor for the correction of excess air, be able to measure a sulfur compound concentration emission limit of 5 p pm (dry basis, zero percent excess air), which is stoichiometrically equivalent to the limit of sulfur compound content of 40 ppm calculated as hydrogen sulfide in the gaseous f uels; (5) Use District Methods 100.1 or 6.1 (as applicabl e for sulfur compound analysis) and SCAQMD Method 3.1 (for oxygen content analysis), or SCAQMD Method 2.1 (for flowrate determination), whichever is applicable, o r any other methods demonstrated byAVAQMD Rule 431.1 Sulfur Content of Gaseous Fuels 431.1-10 the applicant to be equivalent and approved in writ ing by the APCO and the CARB, and the Regional Administrator of the EPA, Region IX, o r their designees, for conducting the relative accuracy evaluations. The relative accura cy limit shall be 1 ppm and zero drift (2-hour and 24-hour) and calibration drift (2-hour and 24-hour) limits for sulfur compounds monitor shall be 5 percent of the span ra nge; and (6) Check for calibration drift of the monitoring s ystem at least once daily (approximately 24- hr interval) at two concentrations, one high level and one low level. Whenever the daily high level or low level calibration drift exceeds 5 % of analyzer full scale span, the monitoring system shall be deemed to be out of cont rol and subject to the requirements of subsection (D)(2)(b) of this rule. (7) Facilities burning fuel gas subject to this rul e shall comply with the requirements of Rule 218 and 218.1(proposed) except where specific requi rements have been incorporated into this rule.

SECTION III –

GUIDELINES FOR APPROVAL OF ALTERNATIVE MONITORING PLAN

BY THE APCO

In lieu of a continuous fuel gas monitoring system (CFGMS) or a continuous emission monitoring system (CEMS), a person subject to this rule may submit an alternative monitoring plan to the APCO, the California Air Resources Board (CARB), and the Regional Administrator of the Environmental Protection Agency (EPA), Regio n IX, or their designees. for their review and decision.

(1) A test program to determine the correlation bet ween H 2 S and total sulfur in the fuel gas using SCAQMD Method 307-91. If a correlation is es tablished, a colorimetric test, or other alternative method approved by the APCO as be ing equivalent or better in establishing such correlation, may be conducted reg ularly to determine total sulfur using H 2 S as a surrogate. (2) An error analysis between colorimetric, or othe r approved alternative method readings and the total reduced sulfur analysis obtained from SCAQMD Method 307-91. To demonstrate equivalency between the two methods of analyses, the relative accuracy shall not exceed 20 percent of average SCAQMD Method 307- 91 readings. (3) A schedule for a daily or more frequent analysi s of the fuel gas for H 2 S using the colorimetric test, or other approved alternative me thod, and a minimum weekly analysis of the fuel gas using SCAQMD Method 307-91. A diff erent frequency of analysis may be used if the APCO determines that such frequency will ensure compliance with the daily total sulfur limits of this rule. (4) When the sulfur level is suspected to be at or above the sulfur content requirements of Table 1 as determined by the colorimetric or other alternative method, a procedure to obtain at minimum a daily sample to be tested accor ding to SCAQMD Method 307-91 until three consecutive daily samples show that tot al sulfur is below the sulfur content requirements of Table 1.